I'm running that same setup on my 89 535. The M30 and M50 exhausts are the same eventhough the engine displacement is different. I like it. It went on the car and hung straight with no problems (unlike an ansa I used on my old E30). The sound is awesome and it seems to help in the high rpm range. I couldn't really tell that much difference from the old blown out stock system until I hit 5500 rpm, then it seemed to lunge for the rev limiter. Also I noticed a slight improvement on highway mileage, But being in Germany, mine usually turns 4500 to 5000 when going cross country. I don't know if that will hold true at lower engine RPM'sHTH, Jeff